Synthesis of Chiral 5-Deazaflavin Derivatives and Their Use in Asymmetric Reduction of Ethyl Benzoylformaten

Abstract

Some 1, 5-dihydro-5-deazaflavin (1, 5-dihydropyrimido [4, 5-b] quinoline-2, 4 (3H, 10H) -dione) derivatives possessing chiral substituents at the N-3 position were synthesized. Asymmetric reduction of ethyl benzoylformate in the presence of magnesium perchlorate was carried out with these chiral 1, 5-dihydro-5-deazaflavin derivatives to give ethyl mandelate in moderate optical and chemical yield. The influence of metal additives other than magnesium upon the asymmetric induction and yield of the reduction was investigated, and it was suggested that intermediate ternary complexation is probably involved in the reaction. No improvement of chiral induction was obtained by changing the metal catalyst.